A new study by Dr. Gary Steinman shows that women who drink milk are 5 times more likely to have twins than women who don’t eat or drink any animal products.

The study compared the number of twins born to women who ate a regular diet, vegetarians (who do consume dairy products), and vegans (no animal products).

Gary Steinman believes that levels of IGF (insulin-like growth factor) may be involved. IGF is released from the liver in response to growth hormone. It results in ovaries being more sensitive to follicle stimulating hormone – which increases ovulation.

Since IGF enters milk, including cow’s milk, this may be why milk drinkers have a greater chance of having twins. Vegans have a 13% lower level of IGF in their blood.

Some women just naturally have higher levels of IGF. Black women have higher rates of twin births and they also have higher levels of IGF in their blood. Asian women tend to have much lower IGF levels and also the lowest rate of twin births. Caucasian women have levels some where in between.

Also, in cows, genes that influence the chance of having twins are near the gene for IGF.

Possible explanations for the number of twins has increased in the last 30 years include fertility treatments, women delaying pregnancy and hormones fed to cows.

Gary Steinman works at the Long Island Jewish Medical Center in New Hyde Park, New York and this study appears in the Journal of Reproductive Medicine, in the May 2006 issue.

3 Responses to 'Got twins?'

The study is a crock. First of all, Steinman himself has authored other studies on twins. Among his “findings”: Low calcium (as in not enough milk and dairy in the diet) can also lead to higher rates of twin births. Likewise he’s reported that women who conceive whil breast feeding are nine times more likely to have twins.

On top of all of this is the fine print in this recently published study. Most of his vegan mother data come from the Farm (hippy commune in Tennessee) and are reported through “personal communications” with the Farm’s head of midwifery. This one person reported more than 800 births from 1970 to 1983 as being to vegan women, with only three sets of twins in the bunch. So basically, Steinman’s study looks at some numbers other studies have generated and compares them with the number an old hippy midwife tells him and this is reported as scientific evidence. Clearly it’s not. The figure that says vegans have 13% less IGF in their bodies than others does not come from the Farm sample. The truth is that there were no measurements taken or reported for the Farm sample.

Furthermore, Steinman fails to explain that the human body produces as much IGF in ONE DAY as you can find in 3,000 quarts of milk. The IGF in milk is digestible. For a few servings of dairy a day create a difference of 13% in IGF levels is mathematically impossible. What is known is that people who have lower nutritional intake have less IGF because their bodies don’t produce it.

All Steinman has is a hypothesis and a poor one at that, because much of what he cites in his own bibliography points to all the factors that are known to cause higher rates of twins–age, nutrition, race, fertility treatments, etc. People in the U.S. eat plenty, the demongraphic makeup continues to change and women wait later in life to have families. On top of all this, an increasing number of women use fertility treatment.

Based on this hypothesis, Steinman publishes comments telling womenb to forego dairy and meat (two entire food groups) because he says but cannot prove they are more likely to have twins. He obviously isn’t too worried about osteoporosis or anemia . . .

Trisha said,

on June 1st, 2006 at 12:48 pm

Thank you! Somehow it doesn’t surprise me, I tend to be very skeptical about studies that are more or less correlational types of things. It’s just too simple. This one I didn’t check into too carefully – I should have.

I didn’t like the way he was suggesting that women avoid dairy either (among other things).

Thanks for stopping by! And please if I post something here again that you think isn’t good science – let me know!

The study may well be a crock, but I’d like to point out that “meat” is not a food group. “meat” is one possible component of a group that also includes legumes and nuts.

Excluding meat or dairy from a diet in no way ensures anemia, nor does it guarantee osteoporis. Statements to the effect that they do reflect a bias just as strong as that of the original offending press release.